map

state_popup_2 <- ifelse(states45$CAMPS >= 1, 
                         paste0("<strong>Country: </strong>", 
                      states45$NAME, 
                      "<br><strong>Concentration Camp(s): </strong>", 
                      states45$CAMPS,
                      "<br><strong> Start Year: </strong>", 
                      states45$START_YEAR),
                         paste0( "<br><strong> Country: </strong>", 
                      states45$NAME))

m <- leaflet(states45) %>%
  addTiles() %>% 
  addPolygons(color = "#444444", weight = 1, popup = state_popup_2, smoothFactor = 0.5,
              opacity = 1.0, fillOpacity = 0.5,
              fillColor = ~colorBin("YlOrRd", CAMPS)(CAMPS),
              highlightOptions = highlightOptions(color = "white", weight = 2,
                                                  bringToFront = TRUE))
m